sass Scss useful mixins Pure css3 pointer arrows with outline border

Example

!!! Container should be positioned relatively or absolutely

$direction - top, bottom, left, right

$margin - margin by the edge in $direction. For top and bottom direction - it's from left to right. For left and right - it's from top to bottom.

$colors - first is a border color, second - is a background color (maybe it's better to inherit background color from a parent)

$arrowSide - is a relative size of an arrow

$isInset - arrow is inside (true) or outside of it's container

Here is a working Plunker https://plnkr.co/edit/PRF9eLwmOg8OcUoGb22Y?p=preview

%pointer-core {
    content: " ";
    position: absolute;
    border: solid transparent;
    z-index: 9999;
}

@mixin pointer($direction, $margin: 10px, $colors: (#999, $gray), $arrowSide: 8px, $isInset: false){

    $opposites: (
        top: bottom,
        bottom: top,
        left: right,
        right: left
    );

    $margin-direction: (
        top: left,
        bottom: left,
        left: top,
        right: top
    );

    &:before {
        @extend %pointer-core;
        border-width: $arrowSide;

        @if $isInset {
            border-#{$direction}-color: nth($colors, 1);
            #{$direction}: -1px;
        }
        @else
        {
            border-#{map-get($opposites, $direction)}-color: nth($colors, 1);
            #{map-get($opposites, $direction)}: 100%;
        }

        #{map-get($margin-direction, $direction)}: 0;

        margin-#{map-get($margin-direction, $direction)}: $margin - 1;
    }

    &:after {
        @extend %pointer-core;
        border-width: $arrowSide - 1;

        @if $isInset {
            border-#{$direction}-color: nth($colors, 2);
            #{$direction}: -1px;
        }
        @else
        {
            border-#{map-get($opposites, $direction)}-color: nth($colors, 2);
            #{map-get($opposites, $direction)}: 100%;
        }

        #{map-get($margin-direction, $direction)}: 0;

        margin-#{map-get($margin-direction, $direction)}: $margin;
    }
}